Corrosion inhibiting composition and packaging material



Nov. 12,l968 A IRSC 3,410,711

CORROSION INHIBITING COMPOSITION AND PACKAGING-MATERIAL Filed Dec. '7, 1964 RATE OF VAPORIZATION AT 100 C. D' DICYCLOHEXYLAMINE I NITRITE A POLYISOBUTYLENE DICYCLOHEXYLAMINENITRITE O POLYISOBUTY LENE PER CENT WEIGHT LOSS INVENTOR. ART" R H ms: H

" Oak/om M A T T'RNf r United States Patent Oflice 3,410,717 CORROSION INHIBITING COMPOSITION AND PACKAGING, MATERIAL Arthur Hirsch, Montreal, Quebec, Canada, assignor to Canadian Technical Tape Ltd., Montreal, Quebec, Canada, a Canadian corporation Filed Dec. 7, 1964, Ser. No. 416,256 Claims priority, applicgtiontganada, Dec. 9, 1963, 8 ,8 V 7 Claims. (Cl. 117-122) ABSTRACT OF THE DISCLOSURE A dispersion for use in the preparation of a corrosion inhibiting packaging material is shown comprising 20-30 parts of dicyclohexylarnine benzoate, 7% to 12 /2 parts of an alkyl amine, 50 to 80 parts of polyisobutylene and 300 parts of a dispersing agent such as toluol. Optionally 1 to 5 parts of dicyclohexylamine acetate may also be employed. A corrosion inhibiting packaging material comprising a flexible backing coated with a pressure-sensitive adhesive layer formed from this dispersion.

The present invention relates to corrosion prevention. More particularly, it relates to a novel packaging material suitable for use in preventing corrosion of metallic surfaces. The deterioration of metallic surfaces, especially those composed of ferrous metals, has been one of modern mans serious problems. The causes for this corrosive deterioration are manifold, some are of a chemical, others of a physical, and still others even of a biological nature. Means to combat this destructive force have been and still are sought after.

In recent times vapor phase inhibitors have been developed which aid in preventing corrosion. These products are usually amine salts with a high vapor pressure. They are effective-only in a cornfined space. The object to be protected must be packaged in a sealed box or carton or must be tightly wrapped. The vapor phase inhibitor is placed in the package alongside the metallic object or is coated on the inside faces of the package. The inhibitor vaporizes and thus creates an anticorrosive atmosphere around the metallic object. US. Patent No. 2,643,176, granted June 23, 1953, to Aaron Wachter and Nathan Stillman, and US. Patent No. 2,717,843, granted Sept. 13, 1955 to Aaron Wachter and Nathan Stillman, and others, teach us the use of such corrosion inhibiting papers. Two major shortcomings of these vapor phase inhibitor impregnated or coated papers are: (a) the need for over-wrap to reduce inhibitor loss, and (b) the need for additional packinging or sealing material.

The need for overwrap material is quite apparent. Since the inhibitor paper depends on its action on a very volatile amine salt, it becomes imperative to take all possible actions to minimize the loss of this volatile chemical. In practice, this requires overwraps, boxes, cartons, or sometimes more drastic protective means depending on storage conditions and duration.

Furthermore, since the inhibitor containing paper forms by no means a tight seal it must be taped, glued or in some other way fastened in order to prevent it from unwrapping.

It is an object of the present invention to provide a method for preserving the metal surfaces and in particular ferrous surfaces against corrosion without the necessity of having the source of the inhibitor within close proximity to those surfaces.

Another object of this invention is to provide a packaging material which will act as a carrier for a corrosion inhibitor. Other objects of this invention will become 3,410,717 Patented Nov. 12, 1968 quite apparent from a study of the following detailed description and the cited examples.

Our new corrosion inhibiting packaging material consists essentially of: (A) a flexible backing, (B) an adhesive coating thereon, and (C) a corrosion inhibiting amine salt dispersed in the adhesive coating. The flexible backings may be chosen from a variety of papers, films, foils, or fabrics. Selection of proper flexible backing will be guided by many factors such as: the size and shape of objects to be packaged, storage and shipping conditions, storage or shipping duration, and others.

The preferred choice of adhesive is one which possesses pressure sensitive properties. This means that the packaging material can be sealed without the use of solvents or heat to activate the adhesive coating. The mere application of minor pressure will effect the desired seal. It is furthermore preferred to employ an adhesive which will evince little or no adhesion to any surface save itself. Such an adhesive requires no release backing on the flexible packinging material and leaves no adhesive residues on the packaged metallic object. However, other types of adhesives may be used as well in the successful practice of this invention.

The corrosion inhibitor may be selected from among a large number of amine salts. Table 1 summarizes experiments designed to ascertain the relative effectiveness of various amine salts in preventing corrosion. Selection of the appropriate inhibitor is further aided by a study which is summarized in Table 2. The rates of vaporization determined, enable the formulator to select a product with a reasonable long shelf life. An intelligent appraisal of Table 1 together with Table 2 leads one to conclude that dicyclohexylamine benzoate is preferable to dicyclohexylamine nitrite.

TABLE 1.-EFFECT OF AMINE SALTS UPON CORROSION or IMMERSED TEST PANELS Percent Weight: Change Visual inspection after 24 hours immersion at 60 C.

Test Solution Containing 5% Blank Diethanolamine-nitrite Dlethylenetriamine-carbonate... D icyclohexylamine-oxalate 0. 02 Badly corroded.

Perfect.

Dull spots.

Uniform grey-green coating.

Dull.

A few spots.

Perfect.

Dicyclohexylamine-earbonate D icyclohexylamine-nitrite. Dieyclohexylamine-benzoate.

TABLE 2.RATE OF VAPORIZATION OF AMINE SALTS Percent Weight Change The benzoate performs better than the nitrite on the corrosion emersion test and has a lower rate of vaporization. The benzoate should thus perform as well or better than the nitrite and last much longer. However dicyclohexylamine benzoate is insoluble and diflicult to disperse. If a smaller amount of an alkyl amine is incorporated in the mixture the inhibiting properties are enhanced. A smaller proportion of a faster acting, higher rate of vaporization, amine salt, may be employed as well.

In the accompanying drawing, the single figure is a graph showing that the rate of vaporization of the corrosion inhibitor is retarded by incorporating same into the adhesive and this is an important advantageous fea- .ture of the invention in that the period of useful performance of the corrosion inhibitor is prolonged considerably.

To illustrate the invention we may cite several examples of formulations, which have been coated on flexible backing and have performed Well as packaging materials designed to inhibit corrosion of metallic objects.

The alkyl amine aids in the dispersion of the insoluble dicyclohexylamine benzoate and enhances the inhibiting properties of the salt. The preferred amine of this invention is butylamine. However, other primary as well as secondary amines may be employed. Good results have been obtained with ethylenediamine, diethylamine, dicyclohexylamine, diethylenetriamine, and others.

The polyisobutylene of formulations cited herein is that manufactured by Enjay Company under the trademark Vistanex, The grades most suitable for this invention are Vistanex L80 and LMMS. It is preferable to employ mixtures of those, in which the L-80 is in a ratio of from 10+1 to +1 to that of the LMMS.

The proportion of solvent given herein is only as a guide line and must be adjusted to accommodate coating equipment and conditions.

EXAMPLE 2 Parts Dicyclohexylaminebenzoate 20-30 Dicyclohexylarnine acetate 0-5 Butylamine 7 /2-12 /2 Polysisobutylene 5080 Toluol 300 This formula differs from the previous one in one respect only, namely the incorporation of dicyclohexylamine acetate. The reasons for this addition have been discussed in previous paragraphs,

I claim:

1. A dispersion of use in production of a corrosion inhibiting packaging material comprising -30 parts of dicyclohexylaminebenzoate, 7 /2 to 12 /2 parts of an alkyl amine, 50 to 80 parts of polyisobutylene and 300 parts of a dispersing agent.

2. A dispersion as described in claim 1, said amine being butylamine and said dispersing agent being toluol.

3. 'A dispersion as described in claim 2, including up to 5 parts of dicyclohexylamine acetate.

4. A corrosion inhibiting packaging material comprising a flexible backing, a pressure-sensitive adhesive coating upon one side of said backing comprising 50-80 parts of an adhesive material and dispersed therein a corrosion inhibiting substance composed of 2030 parts of dicyclohexylamine benzoate and 7 /2 to 12% partsof an alkyl amine.

5. A corrosion inhibiting packaging material as described in claim 4, including up 'to 5 parts of dicyclohexylamine acetate, p

6. A corrosion inhibiting packaging material as de.- scribed in claim 5, said pressure-sensitive adhesive being polyisobutylene.

7. A corrosion inhibiting packaging material as described in claim 6, said amine being butylamine.

References Cited UNITED STATES PATENTS 2,357,662 9/1944 Kemp 1 l7122 2,898,026 8/1959 Aid 229.l l 2,937,109 5/1960 Bartell et a1 l17122 3,132,041 5/1964 Pihl l1776 WILLIAM D. MARTIN, Primary Examiner. B. PIANALTO, Assistant Examiner. 

